Inspection Procedure 17: Variable Geometry Control Solenoid Valve System










OPERATION



  • Power is supplied to the variable geometry control solenoid valve (terminal No. 2) from the engine control relay (terminal No. 2).
  • The engine-ECU (terminal No. 44) makes the power transistor in the unit be in "ON" position, and that makes currents go on the variable geometry control solenoid valve (terminal No. 1).

FUNCTION



  • In response to a signal from the engine-ECU, the variable geometry control solenoid valve controls the boost pressure.

PROBABLE CAUSES



  • Failed variable geometry control solenoid valve
  • Open/short circuit or harness damage in variable geometry control solenoid valve circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: A-62 variable geometry control solenoid valve connector

Q. Is the check result normal?
Go to Step 2 .
Repair or replace the connector.

STEP 2. Perform voltage measurement at A-62 variable geometry control solenoid valve connector.

  • Disconnect connector, and measure at the harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 2 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 4 .
Go to Step 3 .

STEP 3. Connector check: A-33X engine control relay connector

Q. Is the check result normal?

    Check and repair harness between A-62 (terminal No. 2) variable geometry control solenoid valve connector and A-33X (terminal No. 2) engine control relay connector.

    • Check power supply line for open/short circuit.
Repair or replace the connector.

STEP 4. Perform voltage measurement at B-27 engine-ECU connector.

  • Disconnect connector, and measure at the harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 44 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 8 .
Go to Step 5 .

STEP 5. Connector check: B-27 engine-ECU connector

Q. Is the check result normal?
Go to Step 6 .
Repair or replace the connector.

STEP 6. Check harness between A-62 (terminal No. 1) variable geometry control solenoid valve connector and B-27 (terminal No. 44) engine-ECU connector.
note Before checking harness, check intermediate connector A-11, and repair if necessary.

  • Check earthing line for open/short circuit.

Q. Is the check result normal?
Go to Step 7 .
Repair the damaged harness wire.

STEP 7. Check the trouble symptoms.

Q. Does trouble symptom persist?

Replace the variable geometry control solenoid valve.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 8. Connector check: B-27 engine-ECU connector

Q. Is the check result normal?
Go to Step 9 .
Repair or replace the connector.

STEP 9. Check harness between A-62 (terminal No. 1) variable geometry control solenoid valve connector and B-27 (terminal No. 44) engine-ECU connector.
note Before checking harness, check intermediate connector A-11, and repair if necessary.

  • Check earthing line for damage.

Q. Is the check result normal?
Go to Step 10 .
Repair the damaged harness wire.

STEP 10. Check harness between A-62 (terminal No. 2) variable geometry control solenoid valve connector and A-33X (terminal No. 2) engine control relay connector.

  • Check power line for damage.

Q. Is the check result normal?
Go to Step 11 .
Repair the damaged harness wire.

STEP 11. Replace the variable geometry control solenoid valve.



  • After replacing the variable geometry control solenoid valve, re-check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU.
The check is end.